Abstracts

T1361

Utility of Kudo Pit Pattern for Distinguishing Adenomatous from

Non Adenomatous Colonic Lesions In Vivo: Meta-Analysis of

Different Endoscopic TechniquesVenkataraman Subramanian, Jayan Mannath, Chris J. Hawkey,Krish RagunathBackground: The pit pattern classification system proposed by Kudo is beingincreasingly utilized as a tool to predict histology of colorectal lesions withsensitivities of over 90% reported in expert hands. Chromoendoscopy,magnification endoscopy, narrow band imaging (NBI) and Fuji intelligentchromoendoscopy (FICE) are all techniques adopted to improve pit patterndetermination. Accurate colonoscopic assessment in vivo has been advocated toavoid the need for histopathology and reduce costs. Aims: To do a meta-analysis ofthe utility of Kudo pit pattern classification in distinguishing adenomatous and nonadenomatous colorectal lesions. Methods: We searched several electronic databasesfor studies which utilized Kudo pit pattern classification for characterization ofcolorectal lesions compared with histology (gold standard). The endoscopicmethods used to characterize the pit pattern were also recorded. A random effectsmeta-analysis with correction for over dispersion was done to pool data within thespecified subgroups based on the endoscopic method used. Heterogeneity wasevaluated using chi square and I2 test. Results: A total of 36 studies evaluating27,388 polyps were included. The pooled sensitivities, specificities, diagnostic oddsratios and AUROC (area under the receiver operating curve) are given in Table 1.Conclusions: This is the first meta analysis ascertaining the utility of Kudo pitpatterns. The accuracy of Kudo pit pattern to distinguish adenomas depends on theendoscopic technique used. Sensitivities of over 90% can be achieved by ME withCE. The diagnostic odds ratio for ME with CE seems significantly better than WLE,ME or CE alone. This was the same for small polyps under 10 mm as well. Using MEwith CE more than 90% of adenomatous polyps can be identified in vivo.

Endoscopic Sensitivity Specificity Diagnostic Odds AUROC

Method (9

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5% CI) (9

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5%CI) R

aio (95% CI) (S E)

All Polyps

White lightendoscopy (WLE)

7

1.9 (68.8-74.8) 7 3.3 (68.3-77.9) 7.4 (3.4-16.2) 0 .79 (0.04)

Magnificationendoscopy ME)

8

0.1 (78.3-84.4) 8 1.4 (84.4-87.0) 19.8 (11.8-27) 0 .88 (0.02)

Chromoendoscopy(CE)

8

7.9 (86.1-89.6) 8 4.7 (82.5-86.8) 32.1 (21.9-46.8) 0 .92 (0.01)

Magnification withchromo (ME þCE)

9

7.1 (96.8-97.3) 7 4.3 (72.7-74.8) 81.8 (53.8-124.3) 0 .96 (0.01)

Narrow Bandimaging

8

7.7 (85.2-89.9) 8 0.8 (77.2-84.0) 35.8 (19.5-65.6) 0 .92 (0.03)

FICE 9

1.6 (89.7-93.3) 8 4.5 (81.6-87.2) 56.7 (20.5-157.3) 0 .96 (0.01) All techniques 9 4.4 (94.1-94.7) 7 8.8 (79.8) 39.5 (29.0-51.3) 0 .92 (0.01) Polyps less than10 mm Chromoendoscopy 8 7.6 (85.4-89.6) 8 4.2 (81.-86.7) 28.7 (15.4-53.7) 0 .91 (0.02) Magnification withchromo (ME þ CE)

9

3.9 (91.6-95.8 8 8.6 (83.0-92.9) 1 11.7 (34.2-364.8) 0 .93 (0.04)

NBI or FICE 8

8.6 (84.2-92.2) 7 7.6 (70.9-83.4) 19.8 (5.7-69.1) 0 .92(0.05) All techniques 8 6.4 (85.1-87.7) 8 3.4 (81.6-83.1) 30.1 (8.6-104.5) 0 .91 (0.01)

T1362

Yield and Cost of Colonoscopy in Patients with Metastatic

Cancer of Unknown PrimaryMehrdad Saliminejad, Shahrooz Bemanian, Joseph Chen, Loren A. LaineMetastatic cancer of unknown primary (MCUP) accounts for up to 10% of cancerdiagnoses. Because cancer therapy relies on knowledge of the primary site,gastroenterologists are commonly asked to perform colonoscopy on patients withMCUP. However, studies evaluating this practice are lacking. We studied patientswith MCUP but without other standard indications for diagnostic colonoscopy todetermine the yield and cost of colonoscopy in this population and any potentialpredictors of a primary colon cancer. Methods: Patients having colonoscopy forindication of MCUP were eligible. Exclusion criteria included familial colon cancersyndromes, prior colon cancer, hematochezia or melena, positive fecal occult bloodtest, iron deficiency anemia, or imaging study suggesting colonic abnormality.Colonoscopy reports from 2004-2007 for outpatients and inpatients seen at L.A.CountyþUSC, USC University and Norris Cancer Hospitals were reviewedretrospectively to identify eligible patients. Beginning in 2008, eligible patients wereidentified prospectively. Costs were based on Medicare reimbursements forcolonoscopy, pathology exam, and surgical professional fee and hospitalization (fora procedural complication). Results: 110 patients were identified: 76 in 2005-2007and 34 in 2008; 73 at L.A. CountyþUSC and 37 at USC University-Norris CancerHospitals. Mean age was 59 yrs (range 28-88) and 59 (54%) were female. Two of the

Vo

110 patients (1.8%, 95% CI 0.2-6.4%) had primary colon cancer identified. Too fewpatients had a colon primary to draw conclusions about predictors, but baselinecharacteristics for those with and without a colon primary are shown in the TABLE.One patient had a perforation due to colonoscopy, which required surgery. Thecost of a strategy of routinely performing colonoscopy in patients with MCUP was$50,662 per colon primary identified. Conclusions: Patients with MCUP but nostandard indications for diagnostic colonoscopy rarely have a primary colon canceridentified and the cost to diagnose one additional colon primary is O $50,000.Whether outcomes are markedly improved in these patients due to moreappropriately directed cancer therapy should be assessed, but routine colonoscopyfor MCUP cannot be recommended at present.

Baseline Characteristics in Patients with and without a Colon Primary

Colon Primary No Colon Primary

lume 69, No. 5 : 2009 GASTR

OINTESTINAL E

Age ! 65 yrs

2/2 75/108 (69%) Lower Abdominal Pain/Discomfort 2/2 47/108 (44%) Constipation 2/2 12/108 (11%) Reduced Stool Caliber 0/2 2/108 (2%) Albumin ! 3.4 g/dl 1/2 51/100 (51%) CEA O 5 ng/ml; CEA O 100 ng/ml 2/2; 1/2 16/55 (29%); 6/55 (11%)

T1363

Small Polyps of the Colon: The Wolf in Sheep’s ClothingDaniel G. Cimmino, Lisandro Pereyra, Jose M. Mella, Federico Popoff,Ignacio F. Caldo, Pablo Luna, Adriana Mohaidle, Carolina Fischer, MarioA. Medrano, Adrian Hadad, Beatriz Vizcaino, Silvia C. Pedreira, LuisA. BoerrIntroduction: The importance of the small colonic polyps has becomea controversial issue due to the implementation of new screening methods forcolorectal cancer that could overlook these lesions. The prevalence of advancedhistological features (AHF) (villous component, high grade dysplasia) in this type ofpolyps is not precisely known. Aim: To determine the prevalence of AHF in smalland diminutive colonic polyps. Methods: Those patients who had undergonea videocolonoscopy and presented small (!9 mm) or diminutive (!6 mm) polypswere identified. Each polyp was analyzed, and the outcomes were expressed inpercentages with their corresponding confidence intervals 95%. A multi-variateanalysis of logistic regression was carried out to search for independent endoscopicpredictors of AHF. Results. In 650 analyzed patients, 1212 polyps were found, 330 Rthan 1 cm, 661 diminutive polyps, and 214 small polyps. The media age of thepatients with diminutive polyps was 63 years old, 51% were men, and the mostfrequent polyps were hyperplastic (HP) (45%), tubular adenomas (TA) (38%),tubulovillous adenomas (TVA) (11.5%), and serrated polyps (SP) (3%). The AHFprevalence in this group was 3.5%, from which 21% were resected with a snareloop, and 8% were elevated with saline solution and stained with Indian ink.Resection was completed in only 25% of the cases. The media age of the patientswith small polyps was 63 years old, 54% were men, and the most frequent polypswere TVA (35%), HP (28%), TA (25%), and SP (6%). The prevalence of AHF polypswas 14%, 90% had been resected with a snare loop, 40% elevated with salinesolution and stained with Indian ink. Resection was completed in half of the cases.In the uni-variate analysis, the following factors were AHF predictors: endoscopist’spresumption, (OR 3.8 IC 2.2-6.6), and the presence of 3 or more polyps in therectosigmoid area, with an absence of other polyps bigger than 1 cm in the rest ofthe colon (OR 0.012, IC 0.009-0.8). In the multi-variate analysis, the followingfactors were independent predictors of AHF: the presence of more than 5 polyps(OR 8, IC 3-25) and the sessile morphology (OR 0.20, IC 0.10-0.38). Conclusion.There is a significant percentage of AHF in small polyps and a lower one in tinypolyps. The resection margin could not be established in most of thepolypectomies. The polyps’ detection and resection strategies can still beoptimized.

T1364

Characteristics of Laterally Spreading Tumours of the

ColorectumNoriyuki Ogata, Hiroshi Kashida, Hideyuki Miyachi, Nobunao Ikehara,Hironari Shiwaku, Yoshiki Wada, Hiroshi Kanie, Fuyuhiko Yamamura,Kazuo Ohtsuka, Shin-Ei KudoBackground: Laterally spreading tumours (LSTs) of the colorectum are defined ascircumferentially extending neoplasms large (R10 mm) in diameter but short inheight. They are usually good indication for endoscopic mucosal resection (EMR)technique because they are rather benign in spite of their large diameter. Thosewith deep submucosal (sm) invasion, however, should not be treatedendoscopically because of higher risk for lymph node metastasis. Aim: To clarifythe nature of LSTs and to determine criteria for endoscopic treatment of them.Methods: A total of 27388 early colorectal tumours were resected endoscopically

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